Dental chair

ABSTRACT

A dental chair comprising a seat portion having a back portion pivotally secured thereto. A lever element is secured at its upper end to the lower center portion of the back portion and is pivotally secured at its lower end to the rearward end of a clevis element. The lever element is pivotally secured, above its lower end, to the seat portion. The forward end of the clevis element is secured to a sleeve which is threaded onto the screw shaft of an electric motor for longitudinal movement thereon. Movement of the sleeve by the screw shaft causes the clevis element to act upon the lower end of the lever element thereby causing the lever element and the back portion to pivot about the pivotal connection of the lever element and the seat portion.

United States Patent 119 Davis, Sr.

[ 4] DENTAL CHAIR 75] Inventor: Roderick W. Davis, Sr., Des Moines, 1

Iowa

[73] Assignee: Den-Tal-Ez Mfg. Co., Des Moines,

Iowa

[22] Filed: Jan. 11, 1973 [21] Appl. No.: 322,756

[52] U.S. Cl. 297/330 [51] Int. Cl A47c 1/02, A47c 1/06, A470 H12 [58]Field of Search 297/330, 341, 342, 346, 297/347, 348, 317, 83, 71;248/421, 3.93

[56] References Cited UNITED STATES PATENTS 3,331,997 5/1968 Fritz eta1. 297/330 3,578,379 5/1971 Taylor et a1. 297/330 3,588,170 6/1971Knabusch 297/330 3,596,982 8/1971 Grams 297/330 July 16, 1974' 3,719,3913/1973 Neri 297/330 v Primary ExaminerPaul R. Gilliam- 57 ABSTRACT Adental chair comprising a seat portion having a back portion pivotallysecured thereto. A lever element is secured at its upper end to thelower center portion of the back portion and is pivotally secured at itslower end to the rearward end of a clevis element. The lever element ispivotally secured, above its lower end, to

the-seat portion. The forward end of the clevis element is secured to asleeve which is threaded onto the screw shaft of an electric motor forlongitudinal movement thereon. Movement of the sleeve by the screw shaftcauses the clevis element to act upon the lower end of the lever'elementthereby causing the lever element and the back portion to pivot. aboutthe pivotal connection of the lever element and the seat portion.

' 9-Claims, 6 Drawing Figures 1 DENTAL CHAIR BACKGROUND OF THEINVENTIONThis invention relates to dental chairs and more particularly to themeans for pivoting the back portion of the dental chair with respect tothe seat portion. The seat backs of conventional dental chairs arecomprised of a heavy frame which surrounds the seat back. The heavyframe is ordinarily constructed of cast metal and is extremelyexpensive. Further, the conventional dental chairs do not have a simplebut efficient means for controlling the pivotal movement of the backportion of the dental chair with respect to the seat portion.

Therefore, it is a principal object of the invention to provide animproved dental chair.

A further object of the invention is to provide a dental chair havingmeans thereon for pivoting the back portion of the chair with respect tothe seat portion of the chair.

A further object of the invention is to provide a dental chair having aback portion comprised of a hollow frame having plywood members andupholstery material mounted thereon.

A further object of the invention is to provide a dental chair having anelectric motor associated therewith for pivotally moving the backportion of the chair.

A further object of the invention is to provide a dental chair having anovel means for pivotally connecting the back portion tothe seat portionof the chair.

A further object of the invention is to provide a dental chair which iseconomical in manufacture, durable in use and refined in appearance.

These and other objects will be apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS This invention consists in theconstruction, arrangements and combination of the various parts of thedevice, whereby the objects contemplated are attained as hereinaftermore fully set forth, specifically pointed out in the claims, andillustrated in the accompanying drawings, in which: 1

FIG. 1 is a perspective view of the dental chair of this invention;

FIG. 2 is a plan view as seen along lines 2 2 of FIG. 1 with portionsthereof cut away to more fully illustrate the invention;

FIG. 3 is an enlarged sectional view seen along lines 3 3 of FIG. 2;

FIG. 4 is a sectional view similar to FIG. 3 except that the backportion has been pivotally moved upwardly with respect to the seatportion;

FIG. 5 is an exploded perspective view of the lever element and cleviselement; and

FIG. 6 is an enlarged sectional 6 6 of FIG. 2.

DESCRIPTION'OF THE PREFERRED EMBODIMENT The numeral 10 refers generallyto the dental chair of this invention comprising a seat portion 12having a view seen along lines I back portion 14 pivotally securedthereto. Seat portion Motor 26 is operatively secured to the brace 20and has a horizontally extending screw shaft extending rearwardlytherefrom. Sleeve 30 is threadably mounted on shaft 28 for longitudinalmovement thereon. The numeral 32 refers to a clevis element havingforwardly ex- I tending arms 34 and 36 which are secured to sleeve 30 bypins 38. Clevis element 32 includes a rearward end portion 40 which isslightly offset with respect to the arms 34 and 36 and which ispositioned in a plane below the arms 34 and 36. Clevis element 32 alsoincludes a pair of rearwardly extending arms 42 and 44.

The back portion 14 is comprised of a hollow frame 46, a front layer ofplywood 48, a rear layer of plywood 50, a detachable back panel 52, andan upholstered gitudinally moved on the screw shaft 28 thereby causingclevis element 32 to act upon the lower end of lever element 58 at 66to" pivot the back portion 14 about 64.

Limit switches 68 and 70 are mounted on the frame 16 in the movable pathof arm 72 which is secured to clevis element 32. The limit switches 68and 70 are electrically connected to motor 26 to deactivate the same atthe extreme limits of travel of the sleeve 30 to prevent damage to thevarious components.

It can be seen from the foregoing that back portion 14, due to theconstruction thereof, is much more economical to manufacture thanexisting dental chairs. It canalso be seen that the novel means forpivotally moving the back portion 14 with respect to the seat portion 12represents a distinct improvement in the art.

' The design relationship between the lever element 58,

a seat portion comprising a frame means and having rearward and forwardend, a back portion having upper and lower ends, anelectric motorsecured to said frame means having a rearwardly extending screw shaft, amember'threadably mounted on said screw shaft for longitudinal movementthereon, a clevis element having rearward and forward ends said cleviselement having a first pair of spaced apart arms at its forward endsecured to said member, and a second pair of spaced apart arms at itsrearward end,

a lever element having upper and lower ends, the upper end of said leverelement being secured to said back portion, the lower end of said leverelement being pivotally arms of the rearward end of said clevis element,

and means pivotally connecting said lever element above its said lowerend to said frame means whereby activation of said motor will cause therearward end of said clevis element to act upon the lower end of saidlever element topivot said back portion about the pivotal connectionbetween said lever element and said frame means.

2. The dental chair of claim 1 wherein said back portion comprises ahollow frame member having front and back panels secured thereto, saidlever element being secured to said front panel.

secured to the spaced apart 3. The dental chair of claim 2 wherein saidpanel has an access opening provided therein in communication with saidupper end of said lever element.

4. The dental chair of claim 1 wherein said second pair of arms dwell ina plane below said first pair of arms.

8. The chair of claim 1 wherein said clevis element has a limit switchactuating arm which deactivates said motor at the extreme limits oftravel of said member threadably mounted on said screw shaft, therebypreventing damage to the components of said chair.

9. The chair of claim 8 wherein the rearward end portion of said .cleviselement is slightly offset with respect to the forward end portion ofsaid clevis element.

1. A dental chair comprising, a seat portion comprising a frame meansand having rearward and forward end, a back portion having upper andlower ends, an electric motor secured to said frame means having arearwardly extending screw shaft, a member threadably mounted on saidscrew shaft for longitudinal movement thereon, a clevis element havingrearward and forward ends said clevis element having a first pair ofspaced apart arms at its forward end secured to said member, and asecond pair of spaced apart arms at its rearward end, a lever elementhaving upper and lower ends, the upper end of said lever element beingsecured to said back portion, the lower end of said lever element beingpivotally secured to the spaced apart arms of the rearward end of saidclevis element, and means pivotally connecting said lever element aboveits said lower end to said frame means whereby activation of said motorwill cause the rearward end of said clevis element to act upon the lowerend of said lever element to pivot said back portion about the pivotalconnection between said lever element and said frame means.
 2. Thedental chair of claim 1 wherein said back portion comprises a hollowframe member having front and back panels securEd thereto, said leverelement being secured to said front panel.
 3. The dental chair of claim2 wherein said panel has an access opening provided therein incommunication with said upper end of said lever element.
 4. The dentalchair of claim 1 wherein said second pair of arms dwell in a plane belowsaid first pair of arms.
 5. The dental chair of claim 1 wherein saidlever element comprises a plate means having an arcuate lower endportion.
 6. The dental chair of claim 1 wherein a pair of spaced apartears are secured to said frame means, said lever element being pivotallysecured to said ears above its lower end.
 7. The dental chair of claim 6wherein said ears extend rearwardly and upwardly from said frame means.8. The chair of claim 1 wherein said clevis element has a limit switchactuating arm which deactivates said motor at the extreme limits oftravel of said member threadably mounted on said screw shaft, therebypreventing damage to the components of said chair.
 9. The chair of claim8 wherein the rearward end portion of said clevis element is slightlyoffset with respect to the forward end portion of said clevis element.